When I pronounce letter ain, there is ghunnah, so how to avoid from the ghunnah?

Question
what are the techniques to pronounce letter ain correctly?
when i pronounce letter ain, there is ghunnah, so how to avoid from the ghunnah?

Answer
This is not an uncommon mistake and is often found in the Muslims from East Asia.
If we don't use the correct articulation point correctly on any letter, we many times compensate with an incorrect component. The most important thing to do is to practice saying the using the correct articulation point: the middle of the throat. Since the letter comes from the same articulation point, and if you pronounce the correctly, you can try alternating between saying a hamzah with a fathah followed by a saakinah, then the same for the rapidly right after one another. You should pinch off your nostrils while doing this to check if you still have a ghunnah. If the sound lessens or disappears while saying the , then you know the ghunnah is still present.
The other thing to practice is driving the sound out through your mouth and not letting the sound go up through your posterior nasal passage.
This will take practice and patience, as it may be that you have been saying it incorrectly for years. As always, we need to turn to Allah in dua' for help in fixing our mistakes and with His help, lots of practice and patience, insha' Allah you will be able to say it properly soon.